Why Desulfurization is Necessary for Steel Refining
Steel refining is a necessary process for producing various grades of steel for a variety of industrial and domestic applications. The process typically involves multiple stages to refine the steel until it meets the target specification. One of the final process steps, desulfurization, is where sulfur is removed either chemically or through the input of electrical current. Two main forms of desulfurization exist: Vacuum Degassing and Electrolytic Degassing. Both of these processes are essential for steel refining and are used to reduce sulfur levels in steel prior to sale and productization.
The first use of desulfurization in steel refining was in the mid-1800s. Scientists at the time were realizing that sulfur was a major difficulty in steel production, leading to metal cracks, brittleness and often a poor finish product. While some technical leaps have been made since then in regard to desulfurization, the process has remained essentially the same: sulfur compounds are removed or suppressed from steel during its synthesis.
The three primary sources of sulfur in steel are iron ore, oxides and coproducts. Sulfur in the form of iron ore is introduced to steel in its most elemental form, while other sources usually contain other elements in addition to sulfur. These other elements often exert a negative effect in the steelmaking process, leading to dysfunction and poor product quality. The high sulfur levels must be removed to ensure a satisfactory product.
The most common way to remove sulfur from steel is Vacuum Degassing. In this technique, the steel is heated to an elevated temperature and levels of hydrogen, carbon dioxide, water, and other elements are decreased. This method of desulfurization can be highly successful if done correctly, but there is a risk of introducing new contaminates from the surrounding environment.
Another effective method of desulfurization is Electrolytic Degassing. This technique uses an electric current to reduce the sulfur levels in steel. The current is guided into the steel through a process of anodes and cathodes, which have the effect of reducing or suppressing sulfur and other contaminants present in the steel. Depending on the levels of sulfur that need to be removed, varying levels of electric current can be used to reduce the sulfur quickly and cost-effectively.
Desulfurization of steel is an essential step in producing a strong and reliable product. Steelmakers must take the time to understand the nuances of the process and use the methods that are most effective for the particular application. Without these measures, it is difficult to produce a satisfactory product, leading to costly rework and inefficient production. The cost and time invested in desulfurization processes are essential to reliably supplying strong, high-performing steel.
